This research grant proposal plans experiments on several projects involving enzymatic activation mechanisms. Specifically the project hopes to: 1) Establish the molecular mechanism for the activation of crystalline pyruvate oxidase by phospholipids and related aggregated and monomer amphiphiles. 2) Affinity label the lipid binding site in pyruvate oxidase using carboxyl activated and photoaffinity labeled amphiphiles. 3) Compare pyruvate oxidase activated by proteolysis with lipid activated enzyme. 4) To reconstitute the E. coli pyruvate oxidase-cytochrome b1 electron transport system from individual components. 5) Characterize the heme iron ligands and the amino acid residues at the active and heme binding site of chloroperoxidase which are responsible for the P-450 character of this enzyme. 6) Characterize chloroperoxidase Compound I and horseradish peroxidase Compound X and examine the relationship between these spectral intermediates and the hydroxylating intermediate in P-450 reactions and the halogenating intermediate in peroxidase catalyzed iodination, bromination, and chlorination reactions.